Year Measure 1960 530.66485 1961 557.59929 1962 605.22353 1963 623.51818 1964 683.68555 1965 714.72158 1966 790.7917 1967 881.38325 1968 993.66457 1969 1049.79116 1970 1123.10299 1971 1244.90323 1972 1295.60968 1973 1473.95233 1974 1580.12602 1975 1607.74131 1976 1707.88619 1977 1661.17907 1978 1757.39626 1979 1768.79418 1980 1805.59073 1981 1820.10412 1982 1760.39991 1983 1781.47221 1984 1813.42444 1985 1843.19325 1986 1875.77819 1987 1916.76755 1988 2065.72244 1989 2269.01333 1990 2317.47677 1991 2397.71417 1992 2430.37452 1993 2318.98299 1994 2436.01236 1995 2537.07268 1996 2489.34042 1997 2634.64913 1998 2756.21891 1999 2877.98241 2000 3003.76167 2001 3060.88181 2002 3107.86734 2003 3157.22726 2004 3238.50245 2005 3251.39713 2006 3194.08125 2007 3180.03342 2008 3026.33841 2009 2757.69141 2010 2742.87718 2011 2689.68434 2012 2683.36793 2013 2512.10592 2014 2464.64129 2015 2571.34096